1972 6hp Evinrude Idle Issue

[bob1123]

I have a 1972 6hp Evinrude Fisherman outboard. I've haven't run this motor in 10 or so years. I recently moved and there's a nice lake nearby with a 10hp limit so I'm trying to get it back into shape. When I first started messing with the motor it didn't have spark and the plugs were dry. Had about 75 psi on each cylinder, not great but I've heard these small hp motors can run ok on less. Here's what I've done so far:

1. Removed and disassembled carb, soaked in carb cleaner, and rebuilt with a generic carb kit I got on ebay.
2. Re-sealed lower unit and changed impeller (lower unit had a small leak around the spaghetti seal).
3. Cleaned and gaped points.

Motor will start and run now, but won't idle. I have to keep the throttle above the start position on the tiller to keep it from dying. It seems to run fine with the throttle open. When I get the motor as low as I can, it doesn't seem to respond to changes in the idle mixture screw at all. When the motor dies I have to choke it to get it started again, even when it's warm. Fires up about every time if I choke it first though. Do I need to start over with a higher quality carb kit? I removed the metal plug on top of the carb before I soaked it and replaced it with a fresh plug from the kit while rebuilding. Am I missing something?

 

[kbait]

Is tip of low speed mixture needle broken off in carb?

 

[Crosbyman]

LS needle packing tight...?

 

[racerone]

Some of those " online " carburetor kits might be shoddy.-----There is an orifice for the idle fuel at the carburetor / bowl joint.---Is it clean ?----Did it sit with fuel in the carburetor all these years ?----Does spark jump a gap of 5/16" on a test device ?

 

[Crosbyman]

Some of those " online " carburetor kits might be shoddy.-----There is an orifice for the idle fuel at the carburetor / bowl joint.---Is it clean ?----Did it sit with fuel in the carburetor all these years ?----Does spark jump a gap of 5/16" on a test device ?

look for the side channel that feeds the gas to the upper drip chamber drip holes under the round plug you pulled out and replaced.

the carb gasket must be the correct type to line up with the feeder hole otherwise no gas wil flow up to the idle circuit

blow out everything (all orifices) with carb cleaner ....

remove the LS needle and blow in carb cleaner and confirm the stuff pours out the 3 small holes above the throttle plate

reinstall the carb and retest

 

[ct1762@gmail.com]

just a word of warning: i bought one of those cheap kits a few years ago for a fastwin 10hp. the bowl gasket completely disintegrated in about 5 minutes and took me the best part of an hour to get the pieces out! first and last time for that nightmare.
check to be sure the fuel pump and gasket isn't leaking.

 

[iggyw1]

bob 1123, I had the same issues as you did last season after I rebuilt my carb on my 6 h.p. Evinrude. When it died out, I had to choke it to get it going again. It would not idle slow enough to troll without the choke partially pulled out (partially closed). Turned out to be cheap gaskets in my carb rebuild kit. Looked like they melted and took a differant shape then when they went in, especially the small gasket at the very bottom of the fuel bowl, underneath a brass tube that went to the bottom of the bowl. That gasket was sucked up into this brass tube housing. (I think it is called the siphon tube well). The cheap carb kit was about $15, and then I purchased a good OEM kit that ran about $40. Rebuilt the carb again with that new kit, and it runs like a new motor now.

 

[oldboat1]

The fuel pump diaphragm may have lost its elasticity. The pumps can be rebuilt, but I usually just replace them. You might try one of the cheap ones and see if it makes a difference.

 

[racerone]

Is there a thermostat in this motor ?------I often find the thermostat missing or stuck open.

 

[bob1123]

Update! I checked the low speed needle and it looked fine. I added another cork packing washer to the low speed needle and now it idles and responds to low speed needle adjustment! It won't idle for long without working the priming bulb though. Going to replace fuel lines first, then fuel pump if new lines don't improve.

 

[bob1123]

Update #2 Replaced fuel lines, that didn't help so I ordered a new fuel pump. Got the pump in the mail today and installed it. Motor would start and run at higher speeds, but didn't want to idle again. It would try to idle for a half second then die immediately. Interesting because I had it idling two weeks ago. I messed with it for a couple minutes today then broke the starter rope. I also checked the thermostat and it was stuck open. Ordering new rope and thermostat/gasket/seal.

 

[bob1123]

Update #3 Finally got my new thermostat/gasket and starter rope installed. At first the motor didn't want to idle again so I messed with the packing around the needle. Now it idles great! Runs nicely in a trash can. Need to get it out and lake test soon.

 

[Rick.]

Glad for you. You pursued and won.

 

[bob1123]

Update #4 Boat tested the motor today. It was hard to start cold, but ran fine once I got it going. The motor seems to only want to start when I give it a lot of throttle. I'm having to choke it and twist the throttle to "FAST" to get it to start. The little motor idled down and shifted perfectly.

 

[iggyw1]

Update #4 Boat tested the motor today. It was hard to start cold, but ran fine once I got it going. The motor seems to only want to start when I give it a lot of throttle. I'm having to choke it and twist the throttle to "FAST" to get it to start. The little motor idled down and shifted perfectly.

Does it start on "fast" within one or two pulls for you? If so, I would live with it. That's how mine starts good too, usually on the first pull but sometimes on the second or even a third pull. The only thing I may add is that when mine starts, I "quickly" grab the throttle control arm and turn it down so I do not get too many RPM's when the motor is cold and in neutral. My problem I had previous to this with starting it cold was my choke was not closing 100%. It is now.

 

[bob1123]

iggyw1:

It normally starts on one or two pulls with the throttle set to "Fast". Sounds like a chainsaw, revs like crazy, and smokes a lot. I try to rev it down as quickly as I can. Hopefully revving a cold motor like that won't score cylinders or make problems down the road.

 

[iggyw1]

iggyw1:

It normally starts on one or two pulls with the throttle set to "Fast". Sounds like a chainsaw, revs like crazy, and smokes a lot. I try to rev it down as quickly as I can. Hopefully revving a cold motor like that won't score cylinders or make problems down the road.

I'm not a mechanic by no means, but when mine starts, it revs a bit too before I get to the throttle as quick as I want to, but by the amount of smoke I get when it first starts, I really am not worried about the pistons for the two seconds of over revving it when it starts. I think the smoke is from the oil sitting on the walls and on the pistons when the gas has evaporated, so this is extra protection for me. (in my mind) LOL . I may be way off base on this & I think if I am, I will be corrected from someone that will know for sure that I am wrong. I do not have to put my throttle at wide opened, but faster than I want to have it for a cold start up/